Dust collection strategy

Well, looks like I am a lifer in the woodworking world. The hobby has stuck and I am starting to transform my 2 car garage we don’t park cars in from a storage shed/crap dump/work area to a real dedicated workshop. My next consideration is dust collection. Even though the place is kind of a mess now, I still break out the shop vac after every cutting operation. I haven’t narrowed down the equipment I will be getting yet, however I need some tips as far as plumbing I want to run plumbing on the 3 walls without doors. My Table saw and band saw will be on one side of the shop, the drill press, band saw, jointer and router table on the other. I would also like a dust port drop off at all 3 of my work benches for when I do sanding/hand held routing. I want to run hard pipes along the wall with flexible hose to the tools. After my long explanation, here are my questions:

1 – most DC systems I have seen have one inlet. Is that the case?2 – PVC or ABS?3 – should I be worried about loss of suction if I have 6+ ports hooked up to dust collection at all times? 4 – 2.5” hard pipe instead of 4” to the router table, band saw and work benches, or run 4” and reduce it at the tool? All of those things have 2.5” ports.

I picked up on a neat trick at my lumber mill. When they go between the jointer and planer, they insert a thin piece of sheet metal into a slot cut in the port that goes back to the DC on the machine not in use. Is that overkill or something I should consider?

42 replies so far

Most small systems will only function correctly with one port open at a time. In some cases, two ports work.

By small systems I mean 2HP collectors and yes they usually have one 5” inlet.

It would be best to use 5” duct, but that is not something easily found, and expensive if you do find it..

By two ports I mean a 4” and a 2 1/2” open at the same time. A setup used on router tables and table saws sometimes; 4” to the saw base and 2 1/2” to the table top blade guard for example.

I think what you refer to with the “sheet of metal in a slot in the port” is a homemade version of a blast gate.Sheet of metal in a slot will have leakage that will rob the system of performance. Buy or make true blast gates for this function.

That “thin piece of metal” is called a blast gate. :) Your suction goes down as you add length to the pipe. So the farther away you are from that DC, the less suction you’ll have. Elbows also decrease suction equivalent to about 10 feet of pipe (each). I only have a couple machines I absolutely need on DC. My table saw and my planer. I want to put in some hard pipe so I can have other stuff on the DC, but it hasn’t happened yet and it seems like I always have something else to do. Table saw and planer have quick connects and I have a 10ft flexible hose and I disconnect from table saw and connect to planer or the other way around depending on what I’m doing. Only takes a second. My shop is only like 1 and a half car garage size so I can roll my DC if I have to (for instance) position the planer closer to the door so I can pass long boards through it. (Stand outside to feed it into the planer….. we don’t all have big shops … hehehhe)And… I only run one piece of equipment at a time generally. I don’t usually take a board, pass it through the planer, and then take it right to the table saw. Usually I’d pass everything through the planer and then I’m done with it. THEN go to table saw and do all THOSE cutting operations. For that reason alone, you might consider putting your DC on a cart or just get one that rolls. Take it where you use it.You can get “Y” adapters so that’s not a problem.You can spend a lot of money on a DC capable of handling long pipe runs. Then you move a piece of equipment and you have to repipe to it. Think about it.

I will say that HAVING a dust collector is far better than NOT having a dust collector.

1 – Well, they kind of have to only have one inlet, right? Many, like my PM-1300 has an adapter installed taking the 6” to two 4”, but can be removed. If you’re running duct you should go with the one big inlet.

2 – PVC or metal is usually the question. Both can work fine. I suppose ABS can work too, but I think it would be pricey for an entire system. I’d make the call based on price and what’s easily available to you. Pentz recommends PVC sewer and drain pipe, thin walled and cheaper than schedule 40 stuff. Also seems to think heavy (26 gauge) home center HVAC duct is OK, just avoid the thin 30 gauge stuff.

3 – As long as you have a way of shutting off the drops that are not in use, you won’t have a problem (blast gates are the usual method.) You can NOT plan on leaving all the machines open to suction all the time and expect to get suction without a pro-shop size system.

4 – In general you want to run as large a pipe as you can for as long as possible, and keep the flex hose to a minimum. Both flex hose (rough interior) and small diameter pipe cause high pressure drop. As a general rule you’re not going to get great suction from a DC through a 2.5” pipe, it’s too small and the DC doesn’t have suction that high. Might be better off with a decent shop vac for 2.5” ports. Better yet, try to increase port sizes to 4” (even converting 4” to 6” is good) which will allow the DC to move enough air to get good collection.

Thanks guys. I was looking somewhere in the area of a 3 hp DC system, like the G0562Z. I would only be using machine at a time, but I want to keep the clutter and trip hazards to a minimum. Thanks for the clarification on the blast gates. I assumed they would cause some loss of suction, but noting as dynastic as 6 open 4” ports. Would putting in something like a ball valve where the pipe goes from hard to flexible work better than a blast gate?

And john, thanks. I have been doing some searching but it just adds to my confusion. I’ll check out that website you referenced, thanks! I asked about ABS because I have access to a lot of ABS for practically nothing.

Blast gates are the way to go. Ball valves are very expensive (try pricing a 4 or 6” ball valve, even a pvc 4” ball valve is over $40), an aluminum 6” blast gate is $12 and 4” is $8 on ebay, plastic blast gates are even cheaper.

I recommend a cyclone separator, a two stage system works fantastic.

I’ll try to post some pics of my system later today.

-- If the old masters had power tools, they would have used them. So get off your damn High Horse.

With a 3HP machine you should be able to run 6” pipe.I have a 2HP collector from HF and it does fine for one machine at a time.

Use no Tees, only Wyes for branches.Two 45 degree elbows are better than one 90 degree elbow. Sweep ells are good.Minimal use of flex duct is good.

It is not true that a 2 1/2” pipe won’t work on a dust collector. Been working on mine for over a year.BUT, you can’t suck big chips, like from a jointer or planer through a 2 1/2” pipe. I use the 2 1/2” duct for sanding dust, and dust from my band saw, stuff like that, and it’s fine.

Caution: Bill Pentz is not an engineer, but he has more than enough ego to be one. Some of his dribble is true, but take it for what it is. Ranting by someone with a giant sense of self worth. Buried in there is some pretty good information. I can interpret most of it because I am an engineer and worked with environmental systems for years, but I think some of his suggestions are way beyond what is reality.

I wish a cyclone separator was in the cards, but the 850 shipped for the griz is already pushing my upper limit. As it is I’ve spent over 3,500.00 on tools in the past 2 weeks, and I still am missing some key tools – like a planer, any kind of hand tool that is not a plastic handled embarrassment, and a drum sander since making cabinets is in my not so distant future. My total tool cap is about 10,000. That also has to include the 2,800 the electrician charged me to rewire the garage. That’s not much to a lot of you and my wife and I do pretty well, but we also have 4 young kids – and I am not a professional so basically these are toys to me, so I do feel a tad guilty.

Michael, yes I will be using Wyes. Does it make sense to put a couple in-line on the longer runs and use them as clean outs (as long as they can be capped off)? I’m not sure how clogged up a 6” pipe can get. Also I see a lot of people use DC for floor sweepers as well. I have just started reading Bill’s site and I am picking up on the self important vibe, but also see some things of value. I have a nice shop vac but I can’t suck up big ribbons from my crappy hand planes. Is that a waste of time or worthwhile?

You need to review the ducting cost for a good system, it will sometimes be as high as the DC itself. That said, most of that cost will be in the fittings and if you want to make things a lot harder you can fashion those yourself….it’s a little easier with PVC, but metal can be worked as well. You could also build your own separator, the Thein model works well. As for floor sweeps, I had 2 in my last shop and never used them…didn’t put them in the current shop and am now planning to add 2 (go figure), but I have a cyclone. With a single stage DC you might sweep nuts/bolts/something that’s metal into the sweep and it might hit the fan and might spark and might cause a fire in your bags…probably more theoretical than real, but keep it in mind. I’m guessing your electrician put in a dedicated circuit for the DC? it’ll draw some amps and always big running when the other big dogs are so it’s best on it’s own circuit. One other thing, in addition to the wyes, you might get some benefit by passing on the tight radius 90° elbows, instead use 2 – 45° ones with a short pieces of straight in between to soften the curve. Just some things to think about.

Thanks Fred. I am estimating my piping costs to exceed 1000.00 including fittings, which is why I would have a really hard time moving any further up the line than the Grizzly G0562Z. That is actually more than the DC itself, but I want to do this once, and do it right. I do have 4 dedicated circuits. two 110v and two 220v, along with a lot of other non-dedicated outlets. I am skilled at pulling cable, so I ran it all to code (or better) and had a licensed electrician terminate and inspect everything. I know DC will need to run along with other tools, as well as air filtration, dehumidifier, and heater in the winter, so at least I got that part planned correctly in advance. Good tip on the 45’s and that is something I had considered. I think I am going to pass on the floor sweeps. I am a little sloppy and always drop screws and vacuum them up in piles of sawdust.

Probably the most overlooked part of a DC system is the blast gates. Like the rest of the DC system, all parts MUST be airtight. Home made blast gates are notorious for leaking and the slightest air leak will degrade any DC system by quite a bit. In use, only one blast gate should be open, allowing for the maximum air flow from that machine; BUT; make sure you always have one blast gate open or you can collapse the ductwork.

I used some of the plastic blast gates that came with my HF DC and I can tell you that they’re junk. After a while they get sawdust built up in them so they don’t close all the way, and even before that they leak. I just recently made a few homemade blast gates out of 1/2” plywood with a 1/4” plywood insert that opens or closes the gate. They work really well and they’re dirt cheap.

Also, your comment about ducting on the three walls that don’t have doors…in my garage I chose to go across the front of the garage (where the door is). I just went right over the top of the garage door with 4” PVC, no problems at all. Just wanted to throw that out there in case you were thinking the door would interfere somehow.

Just a few pics of how my DC system is shaping up.I now have a 3 HP Grizzly DC , The 2 HP Harbor Freight worked fine in my old shop but with the longer ducting runs and the new Unisaw it just didn’t have enough cfm.The cyclone separator came from ebay ($199) I got it about 5 years ago and it works great.

-- If the old masters had power tools, they would have used them. So get off your damn High Horse.

Scot, that’s awesome. If I am not mistaken that is the DC I ordered. I also plan on getting the aluminum blast gates from Grizzly, unless someone confirms they don’t work at all. They seem very reasonably priced. I am still finishing up a project that needs to get done for the boss (wife). After that the garage gets gutted and I start to lay out the pipe. I am going to try to use as little bends a possible when I lay it out.
I am also running copper for compressed air with a few different take offs and putting in water separators. Is condensation a concern with DC plumbing? I have never heard about anyone making provisions for it.

Also one more thing that my father is insistent on that I have yet to see, but it makes sense on paper. He is a mechanical engineer and works in a large manufacturing facility. Vacuums create a lot of static, static can create sparks, sparks + fine dust = fuel-air bomb. He is insistent I run a bare copper wire through the system and earth ground it. That is going to add a considerable cost. Is this standard practice, or overkill?